Case of the Bromate-Sulfite Reaction

This is a more mildly acid-autoactivated reaction. The gross stoichiometry of the activation process is given below  

The 21 -shadowgram snapshots cover 4 h of experiment. In the figure, the swollen states appear brighter than the shrunken states, because the surface of the former is smooth while that of the latter is crumpled. A dark pulse of collapsed polymer gel is seen to propagate from top to bottom, down to a minimal position. The phenomenon repeats a few times. To guide the eyes, the locations of the denser polymer pulses are demarcated by red lines. Behind the dark pulse, the gel reswells 

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